Multi-Protocol Label Switching Transport Profile (MPLS-TP) is a joint International Telecommunications Union (ITU-T)/Internet Engineering Task Force (IETF) effort to include an MPLS Transport Profile (MPLS-TP) within the IETF MPLS architecture to support the capabilities and functionalities of a packet transport network as defined by ITU-T. In the MPLS-TP requirements draft [DRAFT-JENKINS] it is highlighted that an MPLS-TP architecture must allow a smooth migration from legacy networks (e.g. SONET/SDH) to packet transport networks and support, in a reliable way, the accelerating growth of packet-based services (such as VoIP, L2/L3 VPN, IPTV, RAN backhauling, etc.). That migration must be accomplished preserving carriers investments in both Capital Expenditure (CAPER) and Operational Expense (OPEX) as much as possible. Most of the deployed SDHISONET networks around the world are based on ring topologies, this assumption being especially true for Metro-Core and Metro-Access networks.
The most interesting applications leading the network transformation are point-to-multipoint (P2MP) applications, such as Internet Protocol Television (IPTV). It is desirable that MPLS-TP supports an efficient solution for P2MP applications over interconnected rings. It is also desirable that these applications have appropriate resiliency, such as recovery from at least a single node/link failure.